this is your personal decision. you should use your own judgement.
but let me tell you something about these jobs in general if you are now in US.
Tech support usually considered the lowest level of job, while sales may not sound too good, but better than tech support
I fully understand that the job title in China could be different and you may get a great chance to switch department. But as of right now, if you were in US, sales job looks better on resume.